Rock bit



July 5, 1 938.

A. C. CATLAND ROCK an:

Filed Dec. 24, 1935 3 Sheets-Sheet 1 ATTORNEY July 5, 1938. A. c. CATLAND ROCK BIT Filed 1935 I5 Sheets-Sheet 3 fiya Patented July 5, 1938 UNITED STATES ROCK BIT Alfred C. Catland, Alhambra, Calif., assignor to Globe Oil Tools Company, Los Nietos, Calif., a corporation of California Application December 24, 1935, Serial No.'56,006

11' Claims.

a roller rock bit in which the operating thrusts" resulting from the action of the cutters on the earth formation do not cause or tend to cause spreading of the bit head.

Another object of this invention is to provide a roller rock bit that is operable to drill a straight vertical bore. The cutters of the bit provided by this invention are mounted and related to center the bit in the well bore and to stabilize the bit during its rotation, thereby guiding the bit to make a straight vertical bore. 1

Another object of this invention is to provide a rock bit in which the carrier or spider rotatably supporting the several cutters of the bit is a simple, integral part and is dependably and securely attached to the bit head by simple inexpensive securing means.

Another objectof this invention is to provide a roller rock bit on which the cutters are mounted and related to have active cutting engagement with substantially the entire bottom wall of the well and to be rapid and efiicient intheir cutting action. I

Another object of this invention is to provide a rock bit of the character mentioned in which the spider carrying the rotatable cutters may be quickly detached from the bit head with simple tools to permit the easy replacement of the cut- 40 ters.

A further object of this invention is to provide a roller rock bit, or the character mentioned in which the bit head may be easily and quickly secured to the shank in 'the proper rotative position 45 relative to the discharge ports on the shank so that the circulation fluid properly impinges against and flushes the cutters.

The various objects and features of my invention will be fully understood from the follow- 50 mg detailed description of typical preferred forms and applications of my invention, throughout which description reference is made to the accompanying drawings, in which:

Fig. 1 is a side elevation of the improved rock 55 bit provided by this invention. Fig. 2 is a botftom elevation of the bit with the cutter carrying unit removed. Fig. 3 is a central longitudinal detailed sectional view of the principal partsof the bit illustrating the rotatable mounting of the outer cutters. Fig. 4 is a central longitudinal 5 detailed sectional view of the bit showing the shank in elevation, being a view taken in a plane at 90 to the plane of sectioning of Fig. 3 and showing the rotatable mounting of the inner cut ters. Fig. 5 is a bottom elevation view of the 10 bit. Fig. 6 is a top or plan view of the cutter supporting carrier with the cutters removed. Fig. '7 is a side elevation of the carrier. Figs. 8 and. 9 are transverse detailed sectional views taken as indicated by lines 88, and 99 respec- 15 tively on Fig. 4 and Fig. 10 is a side elevation of the bit with a portion broken away to illustrate another manner of connecting the bit head with the shank.

The improved rock bit provided by this inven- 20 tion includes, generally, a shank [0, a bit head H removably secured to the shank II]. a spider or carrier l2 detachably secured to the head I I, outer roller cutters l3 rotatably supported by the carrier l2 and inner cutting means I 4 supported 5 by the carrier l2.

The shank I0 is adapted to be connected with the lower end of a drilling string of drill pipe and is provided to receive or carry the bit head II.

Inpractice the shank 10 may be an elongate cylindrical member having a reduced lower end portion IS. A downwardly facing annular shoulder l6 occurs on the shank ill at the upper end of its reduced portion Hi. The shank I0 is provided with a central longitudinal fluid passage 3 I l for carrying the fluid downwardly from the drilling string. A fluid discharge block or nozzle I8 is provided at the lower end of the passage I! to discharge the circulation fluid against the cutters l3 and the cutting means Hi. The nozzle 40 I8 is preferably tapered and is accurately or tightly fitted in a tapered socket l9 at the lower end of the passage I! to have fluid tight engage-- ment with the shank H). In practice the block or nozzle l8 may be welded or otherwise fixed to the shank l0. Sets or pairs of diametrically opposite ports 20 and 2| are provided in the nozzle E8. The ports 20 and 2lare provided to discharge the circulation fluid downwardly against the cutters l3 and the cutting means M at an 60 increased velocity as will be hereinafter described. The fluid discharge ports 20 and 2! are preferably inclined downwardly and outwardly.

The head i i may be considered as the body of the bit and is provided to support the carrier i2. The head II is a tubular member surrounding the reduced portion l5 of the shank l and projecting downwardly beyond the lower end of said portion. Sets or pairs of legs 22 and 23 project downwardly from the lower-end of the head ll. Thelegs 22 and 23 are integral parts of the head H and the legs of each pair are diametrically opposite. The diametrically opposite legs 22 are spaced substantially 90 between the diametrically opposite legs 23. The inner surfaces or sides 24 of the legs 22 are inclined downwardly and outwardly as clearly illustrated in Fig. 3 of the drawings. The legs 22 are thickened at their lower ends being provided with inwardly projecting keys or lugs 25. The keys or lugs 25 have substantially horizontal lower sides 26 and inner sides 21 which are substantially vertical or slightly inclined downwardly and outwardly. The inner sides of the legs 23 have upper surfaces 23 which are inclined downwardly and outwardly and lower surfaces 28 which are substantially vertical. The legs 22 and 23 may flare downwardly or project downwardly and outwardly from the lower end of the head II, as illustrated throughout the drawings.

The invention as illustrated "in Figs. 1 m9,-

inclusive, of the drawings embodies a simple, efiective means for removably securing the bithead to the shank ID. This means for connecting the head II with the shank l6 includes lugs 30 projecting from the reduced portion ii of the shank HI at diametrically opposite points.

The lugs 30' are adapted to cooperate with bayonet slots in the head I I. These bayonet slots include vertical branches or. arms 3| extending downwardly from the upper end of the head II and lateral or substantially horizontal arms 32. The slot parts or arms 3| may be in the form of grooves in the interior of the head ll while the arms 32 may extend through the walls of the head to itsouter surface. The shank portion I may have flat faces ID for forming the inner walls of the channels or slot arms 3|. The head I l may be thickened or reinforced at the vertical arms 3| of the slot as shown in Fig. 9 oil the drawings. When the shank l6 and head II are assembled the lugs 30 are entered in the vertical arms 3| of the slots and when they reach thehorizontal arms 32 the head I! is turned relative to the shank to move the lugs 30 into the lateral arms 32 of the slots. When the lugs 30 are received in the slot arms 32 the shoulder l6 may engage the upper end of the head Bars or keys 33 are then introduced into the vertical arms 3| of the bayonetslots to lock the lugs 36 in the slot arms 32. The parts are preferably related so that the keys 33 are entered behind the lugs 30 relative ,to the direction of rotation of the bit. Screws 34 are threaded into openings in the faces 16 of the shank at the upper ends of the keys 33 to prevent the upward displacement of the keys.

The lugs 30 .positively locked in cooperation with the slot arms 32 by the keys 33 form posi tive driving connections between the shank l0 and the head II. The lugs3l| may be easily disengaged from the bayonet slots following the removal of the screws 34 and the keys 33. The releasable-connection between the shank HI and the head ll just described positions the head H in a deiinite or known rotative position with respect to the shank lO-to insure the proper re-' lationship between the ports 26 and 2| and the cutters l3'and the cutting means l4. It is to be understood that the bit head II may be screw-threaded to the shank l0 as illustrated in Fig. of the drawings. In the case where the head II is threadedly connected with the shank III the reduced portion l5 of the shank is suitably tapered and the-shank portion i5 and the interior of the head II are provided with suitable cooperating threads 35 as shown in Fig. 10. When the head Ii is fully threaded on the shank portion l5 itsupper end bears against the shoulder l6.

The spider or cutter carriewlz is provided to support the outer cutters i3 and the inner cutting means and is dependably secured to the legs 22 and 23 for easy removal from the head II to permit replacement of the cutters and cutting means or to permit its replacement together with the cutters and cutting means. In accordance with the invention the carrier I2 is a onepiece or integral member as illustrated in Figs. 6 and 7 of the drawings. The carrier l2 includes a central web 36 which is substantially wedge shaped in vertical cross section having a flat upper end and downwardly convergent sides 31.

The carrier I2 is positioned so that the central longitudinal axis of its web 36 is in or adjacent the vertical plane which includes the central ver- Plate-like parts or tical axes of the legs 22. bosses 38 are integrally joined with the opposite ends of the web 36.- The outwardly facing surfaces or sides 39 of the bosses 38 are inclined downwardly being substantially parallel with the inner sides 24 of the legs 22. Studs or pins 40 project outwardly from the bosses 38 to'rotatably support the outer cutters l3. The pins 40 are integral with the bosses 36 and the web 36 and their longitudinal axes are at right angles to the bosses faces 39 and, accordingly, are substantially normal to the inner sides 24 of the. legs 22.

The outer ends of the pins "are adapted to have bearing or thrust transmitting cooperation with the legs 22. Notches 4| are provided in the outer ends of the pins 40 to receive and cooperate with the lugs 25 on the legs 22. The'notches 4| are shaped to have effective cooperation with the lugs 25 having substantially horizontal bottom walls to cooperate with the lower ends 26 of the lugs and substantially vertical sidewalls to cooperate with the inner sides 21 of the lugs. The cooperation of the notches 4| with the lugs 25 provides for the dependable transmission of operative pressures between tli'e legs 22 and the cutter carrying pins 40. Screws 42 are passed inwardly through downwardly and inwardly inclined openings 43 in the legs 22 and are threaded into longitudinal openings or sockets 44 in the pins 46. The heads of the screws 42 are preferably countersunk in the openings 43. The screws 42 dependably connect the legs 22 with the pins 40 of the carrier1l2. j

.The carrier R -includes or is provided with studs or pins 45 for carrying the inner cutting means H. The pins 45 project"i rom the opposite sides 31 of the web 36 and extend. toward the legs 23. The pins 45 may have their central longitudinal axes lying in the same vertical plane as the vertical axis of the legs 23. In thepreferred construction the pins 45 project down; wardly and outwardly from the web 36 having downwardly and outwardly inclined longitudinal axes. the web 36. Reduced parts 46 are provided on the outer ends of the pins 45. The reduced parts 46 are adapted to cooperate with vertical notches 4! in the inner sides of the legs 23. The end The pins 45 are preferably integral with,

parts 46 of the pins 45 are adapted to bear upe wardly and'outwardly on the walls of the notches 47. Shoulders 48 occur at the inner ends of the reduced parts 46 and are spaced inwardly from the inner sides 28 of the legs 23. The invention includes means for connecting the pins 45 with the legs 23. Screws 49 are passed inwardly through .openings 53 in the legs 23 and are threaded into longitudinal openings in the pins 45. The heads of the screws 49 are preferably countersunk in the openings 50. The screws 49 operate to securely connect the legs 23 and the pins 65.

The outer cutters iii are provided to cut the well bore to gauge and to act on the outer portion of the bottom wall of the well. The outer cutters l3 are in the nature of substantially cylindrical roller cutters and are rotatably supported on the inclined pins 45. Cutting parts or teeth M are provided on the cutters I 3 to act on the earth formation. In the particular case illustrated the cutting teeth 5i are straight and axial, it being understood that the cutting parts of the cutters l3 may be spiralled or otherwise arranged. The outer cutters i3 are preferably supported on the pins 65 through roller bearings 52. Counter-bores 53 in the cutters i3 carry the bearings 52. The outer cutters i3 are supported on the pins ii! so that the surfaces 38 of the bosses 38 form thrust shoulders at the inner ends of the cutters. Replaceable thrust washers 5d are arranged on the lugs to receive the end thrusts from the outer ends of the cutters i3 and to prevent excessive wearing of the legs 22. The thrust washers 5 5 are held against rotation through their cooperation with flat end surface r 55 on the legs 2'2. The outer cutters i3 rotatably supported as just described are rotatable about downwardly and inwardly inclined axes and 'project downwardly beyond the legs 22 and the web 36 to cooperate with the bottom wall of the well and project outwardly beyond the legs 22 to contact the side wall of the well to cut the bore to size. It is preferred to bevel oiT the outer ends of the cutting teeth 5i as at 55 to have proper cooperation with the side wall of the well.

The inner cutting means it is provided to act on the major inner portion of the bottom wall of the well. The means it includes a cutter 5i rotatably supported on each'pin 35 and a cutter 58 supported on each pin 5. The cutters 5i and 58 are roller cutters and are substantially cylindrical in their general configuration. The cutters 5'! are rotatably supported on the inner end portions of the pins 35. The cutters 57 may be alike in size and shape. The cutters 57 are provided with suitable peripheral cutting parts or teeth 59. The inner ends of the cutters 57 may have thrust transmitting cooperation with the sides or surfaces 31 of the web 36. Roller bearings 60 are preferably provided to rotatably support the cutters 5'! on the inclined pins 45.

The cutters 53 of the means M are rotatably supported on the outer end portions of the pins 45. In the preferred form of the invention the cutters 58 are larger in diameter than the cut- The rotatable cutters 58 are provided with suitable peripheral cutting parts 63. Roller bearings 64 may be provided to rotatably support the cutters 58 on the pins 45.

The roller cutters 51 and 58 rotatably supported on the pins 45 as just described rotate about downwardly and outwardly inclined axes leaving or forming a conical mound on thebottom wall of the well bore, which mound is stepped, due to the differences in effective diameters of the cutters. The cutters 5'! and 58 cooperating with this stepped mound of earth formation operate to center the bit during operation and stabilize the bit whereby it drills a straight vertical bore.

With the carrier i2 secured to the head H and the head ii secured to the shank ID by the bayonet slot connection 3G3i32, as described above, the port-s 20 are positioned to discharge the circulation fluid downwardly and outwardly at an increased velocity to impinge against the outer cutters I3 while the ports 2i discharge the fluid at an increased velocity against the cutters 5i and 58.

In operation the rock bit of the present invention is operated on the lower end of a string of drill pipe by rotating the pipe and feeding it downwardly. The lugs cooperating with the branches or arms 32 of the bayonet slots form a positive and dependable driving connection between the shank ID and the head ii. The cutter carrier :2 is attached to and bears on the arms 22 and 23 so that the feeding pressures or drilling Weight on the cutters is effectively transmitted between the head and the carrier without tending to cause the head to spread. The lugs 25 cooperating with the notches fiiil and the reduced parts 871' of the pins 45 cooperating with the slots t? provide for the direct transmission of pressures between the legs of the head it and the cutter supporting pins 49 and 45 of the carrier 62. The screws 42 and 49 dependably secure the carrier it to the head H but are not subjected to severe pressures or forces.

As the drill is rotated and fed downwardly the outer cutters i3 act on and cut away the outer portion of the bottom wall of the well and the bevelled corners 56 of their cutting parts 5i trim the side wall of the bore to gauge. tion of the cutters I3 provides for the formation of an inclined shoulder on the wall of the bore and the cutters acting on this shoulder assist in guiding and centering the bit. The cutters 5i and 58 of the inner cutting means It carried by the downwardly and outwardly inclined pins 55 act on the major portion of the bottom wall of the bore and the inclination of their axes of rotation causes them to cut or form a substantially conical mound. The cutters 51 and 58 acting on this mound dependably center the bit. The cutters 58 being larger in diameter than the cutters 5! cut an annular shoulder in the conical mound of earth formation and this action further assures the proper centering of the bit. When the cutters I3, 51 or 58 have become worn the cutter carrier l2 may be easily removed from the head II by unscrewing the screws 42 and 49. This operation may be carried out with simple available tools. Following the disconnection of the carrier i2 from the head H the cutters may be easily removed from the cutter supporting pins of the carrier. Thebit of the present invention involves simple inexpensive parts and is easily reconditioned for further use after its cutting parts have become worn.

Having described only typical preferred forms The inclina-' and applications of my invention, I do not wish to be limited or restricted to the specific details herein set forth', but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims. 9 Having described my invention, I claim:

1. A rock bit comprising a bit head having sets I of downwardly projecting legs, a demountable carrier at the lower end of the body, a set of pins projecting upwardly and outwardly from the carrier to cooperate with one set of legs, a set of pins of equal length projecting downwardly and outwardly to cooperate with another set of legs, I

pins projecting downwardly and outwardly to cooperate with another set of legs, the last mentioned pins being of equal length, means connecting the pins and the legs together to rerribvably attach the carrier to the head, and roller cutters rotatable on the pins, the, cooperation between the pins and the legs being the sole means -of supporting the carrier on the body.

3. A rock bit comprising a head having two sets of substantially diametrically opposite downwardly projecting legs, a carrier at the lower end of the head including a web whose central vertical plane is diametric or the central longitudinal axis of the head, pins projecting upwardly and outwardly from opposite sides of the web to the legs of one set to have upward bearing engagement on the legs, and pins projecting downwardly and outwardly from the web to legs of the other set to have upward bearing engagement on the legs, roller cutters rotatably supported on the first named pins to act on the outer portion of the well bore, the second mentioned pins being. equal in length and roller cutters rotatably supported on the said second named pins to act on the inner portion of the bore.

4. A rock bit comprising a head having two sets of substantially diametrically opposite downwardly projecting legs, a one-piece carrier at the lower end of the head including a web whose central vertical plane is diametric of the central longitudinal axis of the head, pins projecting upwardly and outwardly from opposite sides 0! the web to the legs of one set, and pins of equal length projecting downwardly 'andoutwardly from the carrier to legs of the other set, roller cutters rotatably supported on the first named pins to act on the outer portion of the well bore, and sets of rotatable roller cutters on the second named pins to act on the inner portion of the bore wall and form a centering mound, the outermost cutter of each or said sets of cutters being of larger diameter than the inner cutters of the set.

5. A rock bit comprising a'shank, a fluid discharge member on the shank having ports oflset from the central vertical axis of the shank, a bit head having downwardly projecting legs, a

spect thereto to provide for the discharge of A fluid from the said ports against the cutters.

6. In a rock bit, two elements, one a shank, the other a bit head, one element having a bayonet slot, a lug on the other element cooperating with the slot to connectthe elements and transmit turning forces, a fluid discharge nozzle on the shank, having downwardly directed ports offset from the central vertical axis of the shank, downwardly projecting legs on the head, a demountable carrier having pins projecting outwardly to the legs, and roller cutters on the pins, the cooperating slot and lug rotatably positioning the head on the shank to have the nozzle ports discharge against the cutters.

7. In a rock bit, a head having downwardly projecting legs, a carrier at the lower end of the head, pins on the carrier projecting outwardly to the legs, there being notches in the outer ends oi'the pins, cutters rotatable on the pins, and lugs on the legs cooperating with notches.

8. In a rock bit, a. head having downwardly projecting legs, a carrier at the lower end of the head, pins on the carrier projecting outwardly to the legs, there being notches in the outer ends of the pins having substantially vertical side walls and. substantially horizontal lower walls,

' cutters rotatable on the pins, lugs on the legs received in the notches and having substantially vertical sides and substantially horizontal ends cooperating with said ,walls-o1 the notches, to transmit forces between the head and carrier, and screws connecting the pins and legs.

9. In a rock bit, a head having downwardly projecting legs, a carrier at the lower end of the head, pins on the carrier projecting outwardly to the legs, there being notches in the outer ends of the pins having substantially horizontal lower walls, rotatable cutters on the pins, and lugs on the legs received in the notches and having substantiallyhorizontal lower ends bearing on said walls.

10. In a rock bit, a head having substantially diametrically opposite. downwardly projecting legs, a one-piece carrier at the lower end of the head including a web whose central vertical plane is diametric of the central vertical axis of the head, and pins of equal length projecting downwardly and outwardly from the web to the legs, and a set of roller cutters on each pin; the outer cutters of the sets being larger in diameter than the inner cutters whereby the cutters act on a stepped centering mound oi formation.

11. A rock bit comprising a shank, a fluid discharge member on the shank having a downwardly directed discharge offset from the central longitudinal axis 0! the shank, a bit head having downwardly projecting legs, a carrier having pins projecting outwardly to the legs, roller cutters rotatable on the pins, and a bayonet type connecting the head with the shank in a definite rotative position with respect thereto to provide for. the discharge oi fluid from the v said ports against the cutters.

' Al'.mm C. CATLAND. 

